No need to panic though, the anti-estrogens Letrzole or Fulvestrant can lower progesterone levels, and combat any progestenic sides. The use of a 19-nor compound like trenbolone also increases prolactin. Bromocriptine or cabergoline are often recommended to lower prolatin levels (20). Testicular atrophy (shrunken balls) may also occur; HCG used intermittently throughout a cycle can prevent this (21). It is also wise for Tren users to closely monitor their cholesterol levels, kidney function, and liver enzymes as Tren has the potential to negatively affect all of those functions. Trenbolone, being a powerful progestin, will also shut down natural testosterone production—even a relatively small dose will keep the testosterone level suppressed for an extended period of time. This can lower libido and cause erectile dysfunction (fina ****). It is essential that you always stack trenbolone with testosterone.